Offline Version - v2.1.0 - General Update

Adds more documents and small bug fixes.

Features:

• Multiple difficulty modes including easy (7 or less letters), hard (more than 7 letters), and practice (frequently incorrect words)
• Auto-grading
• Button to manually add words to practice mode
• A clear cache button to reset all progress
• Ability to get the word spoken slower, the word in a sentence, the word's meaning, and obviously the word itself (using built-in text-to-speech)
• Shortcuts: Press the enter key as a shortcut for checking and the shift key as a shortcut for going to the next word
• Major bug fixes and QoL